Initialisation depot

ESP32/DCC-Bench/SIMPLIFIED_WIRING.md

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+# Simplified Wiring Diagram
+
+## The Key Insight: One Driver for Everything! 🎯
+
+**You only need ONE LM18200 H-Bridge driver** - it handles both DC and DCC modes.
+
+The ESP32 just sends different signals to the same pins depending on which mode you select:
+
+```
+         ESP32-2432S028R
+         ┌─────────────┐
+         │             │
+GPIO 18 ─┤PWM / DCC_A  │───┐
+GPIO 19 ─┤DIR / DCC_B  │───┤
+GPIO 23 ─┤BRAKE        │───┤
+GPIO 4  ─┤RELAY        │───┼──→ To Relay Module
+GND     ─┤             │───┤
+5V      ─┤             │───┤
+         └─────────────┘   │
+                           │
+                           ↓
+                   LM18200 H-Bridge
+                   ┌──────────────┐
+        GPIO 18 ───┤ PWM Input    │
+        GPIO 19 ───┤ DIR Input    │
+        GPIO 23 ───┤ BRAKE        │
+        GND     ───┤ GND          │
+        5V      ───┤ VCC (logic)  │
+        12-18V  ───┤ VS (power)   │
+                   │              │
+                   │  OUT1  OUT2  │
+                   └───┬──────┬───┘
+                       │      │
+                       ↓      ↓
+                   Track Rail 1 & 2
+```
+
+## How It Works
+
+### DC Analog Mode
+When you select **DC Analog** mode in the UI:
+- GPIO 18 outputs **20kHz PWM** (0-100% duty cycle for speed)
+- GPIO 19 outputs **HIGH or LOW** (sets direction: FWD or REV)
+- LM18200 amplifies this to create variable DC voltage on the track
+- Your DC locomotive responds to the voltage
+
+### DCC Digital Mode
+When you select **DCC** mode in the UI:
+- GPIO 18 outputs **DCC Signal A** (square wave: 58μs or 100μs pulses)
+- GPIO 19 outputs **DCC Signal B** (inverted version of Signal A)
+- LM18200 amplifies these to create DCC waveform on the track
+- Your DCC decoder locomotive responds to the digital commands
+
+## Complete Connection List
+
+### LM18200 to ESP32
+| LM18200 Pin | ESP32 GPIO | Purpose |
+|-------------|------------|---------|
+| PWM Input | 18 | Speed (DC) / DCC Signal A (DCC) |
+| Direction Input | 19 | Direction (DC) / DCC Signal B (DCC) |
+| Brake Input | 23 | Emergency stop |
+| GND | GND | Ground reference |
+| VCC (logic) | 5V | Control logic power |
+
+### LM18200 Power & Outputs
+| LM18200 Pin | Connection | Purpose |
+|-------------|------------|---------|
+| VS (motor power) | 12-18V supply + | High current power |
+| GND (power) | 12-18V supply - | Power ground |
+| OUT1 | Track Rail 1 | Amplified output |
+| OUT2 | Track Rail 2 | Amplified output |
+
+### Relay Module (2-rail/3-rail switching)
+| Relay Pin | ESP32 GPIO | Purpose |
+|-----------|------------|---------|
+| Signal IN | 4 | Relay control |
+| VCC | 5V | Relay power |
+| GND | GND | Ground |
+
+### Power Supply Connections
+```
+12-18V Power Supply
+    ├─→ LM18200 VS (motor power)
+    ├─→ DC-DC Buck Converter → 5V → ESP32 + Relay + LM18200 VCC
+    └─→ GND (common ground)
+```
+
+## Why This Works
+
+The LM18200 is just an amplifier. It doesn't care if you're feeding it:
+- PWM signals (for DC speed control)
+- DCC square waves (for digital commands)
+
+It simply takes the 3.3V logic signals from the ESP32 and amplifies them to track voltage (12-18V).
+
+**In DC mode**: The amplified PWM creates variable DC voltage
+**In DCC mode**: The amplified square waves create the DCC signal
+
+## Safety Notes
+
+✅ **Always power OFF before switching modes** (automatic in the UI)
+✅ **Common ground** - All GND connections must be tied together
+✅ **Heat sink** - LM18200 can get hot, use appropriate heat sinking
+✅ **Fusing** - Add fuse on track output for overcurrent protection
+
+## No Separate DCC Booster Needed!
+
+You do **NOT** need:
+- ❌ Separate DCC booster circuit
+- ❌ Different outputs for DC vs DCC
+- ❌ Mode selection switches in hardware
+
+Everything is handled in software by the ESP32 touchscreen UI.
+
+---
+
+**Bottom Line**: Wire up ONE LM18200, and you're done. The ESP32 software handles the rest!